The country had imported 19.43 lakh tonnes of DAP in the year-ago period, according to official data.
"International prices of DAP have come down to USD 440 per tonne this year, from USD 480 per tonne. As a result, there has been a surge in imports," an official said.
DAP is decontrolled fertiliser and the government provides Rs 12,350 per tonne as fixed subsidy on it.
It sells at around Rs 23,000 per tonne in the market for agriculture use and is being imported mainly from China, Saudi Arabia and Russia.